ABSTRACT
Nickel (Ni) resources are found in either sulfide- or laterite-type ores. Natural sources of airborne nickel include soil dust from erosion, sea salt spray, volcano activity, forest fires, meteoric dust, and vegetation exudates. The first known unintentional use of Ni is dated 4000–3500 BC when civilizations of Sumeria, Syria, and the Indus Valley made some bronzes containing over 1% of Ni. Due to rising Ni prices in the global market, in 2005, China could not fulfill its growing demand and found a solution in the form of nickel pig iron (NPI), which is a low-grade ferronickel used for the production of stainless steel. The Ni content of igneous rocks occurring in continental regions is 10 times as high as that from oceanic regions. Ni is constantly cycling between land, water, and air owing to physical and chemical processes including erosion, leaching, and precipitation. Anthropogenic Ni exposure of the environment occurs locally from emissions of metal mining.
